Spring shackle



FIG. 1 is a perspective view of the spring shackle, it being understood that the bolts extending therefrom form no part of the inventive design hereof;

FIG. 2 is a top view, the bottom view being the same as the top view;

FIG. 3 is a right side view, the left side view being the same as the right side view;

FIG. 4 is a front view; and,

FIG. 5 is a rear view. 

The ornamental design for a spring shackle, as shown and described. 